s1$ = "abc def ghi klmnop"
s2$  = "abc"  ' begins with
s3$  = "ef"   ' is in the string
s4$  = "nop"  ' ends with

sn2$ = "abcx"  ' not begins with
sn3$ = "efx"   ' not in the string
sn4$ = "nopx"  ' not ends with

if left$(s1$,len(s2$)) <> s2$ then a$ = "Not "
print "String:";s1$;" does ";a$;"begin with:";s2$

if instr(s1$,s3$) = 0 then a$ = "Not "
print "String:";s1$;" does ";a$;"contain:";s3$

if mid$(s1$,len(s1$) + 1 - len(s4$),len(s4$)) <> s4$ then a$ = "Not "
print "String:";s1$;" does ";a$;"end with:";s4$

' ----------- not -----------------------------
print
if left$(s1$,len(sn2$)) <> sn2$ then a$ = "Not "
print "String:";s1$;" does ";a$;"begin with:";sn2$

if instr(s1$,sn3$) = 0 then a$ = "Not "
print "String:";s1$;" does ";a$;"contain:";sn3$

if mid$(s1$,len(s1$) + 1 - len(sn4$),len(sn4$)) <> sn4$ then a$ = "Not "
print "String:";s1$;" does ";a$;"end with:";sn4$